Non-phenolic color developer and heat-sensitive recording material

Abstract

The invention relates to a color developer of formula (I), (Ar.sup.1SO.sub.2NH)m-Y(NHC(O)NHSO.sub.2Ar.sub.2)n (I), wherein Ar.sup.1 is an unsubstituted or substituted aromatic moiety, Ar.sup.2 is an unsubstituted or substituted phenyl moiety, Y is at least an (m+n)-times substituted benzene group or naphthalene group, and Y is substituted in such a way that at least one Ar.sub.2SO.sub.2NHC(O)NH group is in ortho-position with respect to at least one Ar.sup.1SO.sub.2NH group. The invention further relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive color-forming layer, which contains at least one color former and at least one phenol-free color developer, the at least one color developer being the compound of formula (I). The invention further relates to a method for producing said heat-sensitive recording material.

Claims

1. A heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, wherein the at least one colour developer is the compound of formula (I):
(Ar.sup.1SO.sub.2NH).sub.mY(NHC(O)NHSO.sub.2Ar.sup.2).sub.n(I), wherein Y is at least one benzene group substituted (m+n) times, and Y is substituted in such a way that at least one Ar.sub.2SO.sub.2NHC(O)NH group is in the ortho position with respect to at least one Ar.sup.1SO.sub.2NH group, wherein Ar.sup.2 is an unsubstituted phenyl group or a monosubstituted phenyl group and, wherein Ar.sup.1 is an unsubstituted, substituted or monosubstituted phenyl group, or an unsubstituted or substituted 2-naphthy group, which is substituted with a C.sub.1-C.sub.5 alkyl, an alkenyl, an alkynyl, a benzyl, an RO, a halogen, a formyl, an ROC, an RO.sub.2C, a CN, an NO.sub.2, an RSO.sub.2O, an ROSO.sub.2, an RNHSO.sub.2, an RSO.sub.2NH, an RNHCONH, an RSO.sub.2NHCONH, an RNHCONHSO.sub.2 or an RCONH group, wherein R is a C.sub.1-C.sub.5 alkyl, an alkenyl, an alkynyl, a phenyl, a tolyl or a benzyl group.

2. The heat-sensitive recording material according to claim 1, wherein the at least one colour former is a dye of triphenylmethane, fluorane, azaphthalide and/or fluorene.

3. The heat-sensitive recording material according to claim 1, wherein, besides the compound of formula (I), one or more further non-phenolic colour developers are also present.

4. The heat-sensitive recording material according to claim 1, wherein the compound of formula (I) is present in an amount of from approximately 3 to approximately 35% by weight in relation to the total solids content of the heat-sensitive layer.

5. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive colour-forming layer contains a urea urethane compound of general formula (II) ##STR00005##

6. The heat-sensitive recording material according to claim 1, wherein the compound of formula (I) is present in an amount of from approximately 10 to approximately 25% by weight in relation to the total solids content of the heat-sensitive layer.

7. The heat-sensitive recording material according to claim 1, wherein Ar.sup.1 is a phenyl group.

8. The heat-sensitive recording material according to claim 1, wherein Ar.sup.1 is a C.sub.1-C.sub.5 alkyl-substituted phenyl group.

9. A method for producing a heat-sensitive recording material according to claim 1, wherein an aqueous suspension containing the starting materials of the heat-sensitive colour-forming layer is applied to a carrier substrate and dried, wherein the aqueous suspension to be applied has a solids content of from approximately 20 to approximately 75% by weight, and is applied using the curtain-coating process at an operating speed of the coating facility of at least approximately 400 m/min.

10. A heat-sensitive recording material obtainable by the method according to claim 9.

Description

EXAMPLES

(1) Production of the compounds of formula (I) according to the invention.

(2) The compounds I-XXIV (Table 2) were produced as follows:

(3) Step A1Preparation of the Sulfonamides

(4) A solution of 10 mmol of the corresponding sulfonyl chloride in 75 mL dichloromethane was added dropwise to a solution of 20 mmol aromatic diamine and 20 mmol pyridine in 125 mL dichloromethane at 0 C. under stirring. The reaction solution was stirred for 16 hours at room temperature, before 100 mL water were added. The organic phase was separated and mixed with 250 mL of a 5% aqueous sodium hydroxide solution. The aqueous phase was washed with 100 mL dichloromethane and made neutral by adding 25% hydrochloric acid. After multiple extractions with 100 mL dichloromethane, the combined organic phases were washed with 200 mL water and dried over magnesium sulfate. Following removal of the solvent in a vacuum the sulfonamide remained as a solid. The sulfonamides were used in steps B or C without further purification.

(5) A simple filtration following addition of water to the reaction solution was sufficient to recover the precursor compounds of products IX and XII.

(6) Step A2Preparation of the Sulfonamides

(7) A solution of 80 mmol of the corresponding sulfonyl chloride in 150 mL dichloroethane was added dropwise to a solution of 80 mmol aromatic amine and 240 mmol potassium carbonate in 500 mL dichloroethane at room temperature under stirring. The reaction mixture was refluxed for six hours, and then 300 mL ethyl acetate and 300 mL water were added. The aqueous phase was made acidic by adding 25% hydrochloric acid. The phases were separated. After multiple extractions of the aqueous phase with 200 mL ethyl acetate, the combined organic phases were washed with 200 mL water and dried over magnesium sulfate. Following removal of the solvent in a vacuum the sulfonamide remained as a solid. The sulfonamides were used in step 3 without further purification.

(8) Step A3-Preparation of the Sulfonamides

(9) A solution of 25.0 mmol of aromatic amine in 35 mL abs. THF was added dropwise to a solution of 27.5 mmol sodium hydride (60% in oil) in 25 mL abs. THF at 0 C. under stirring and protective gas atmosphere. After stirring for two hours at room temperature, a solution of 25.0 mmol of the corresponding sulfonyl chloride in 10 mL abs. THF was added dropwise at 0 C. under stirring. The reaction solution was stirred for 40 hours at room temperature, and then 100 mL water and 100 mL dichloromethane were added. The aqueous phase was made alkaline by adding 5% aqueous sodium hydroxide solution. The phases were separated. The aqueous phase was washed with 100 mL dichloromethane and was made neutral by adding 25% hydrochloric acid. After multiple extractions with 100 mL dichloromethane, the combined organic phases were washed with 200 mL water and dried over magnesium sulfate. Following removal of the solvent in a vacuum the sulfonamide remained as a solid. The sulfonamides were used in step B without further purification.

(10) Step BReduction of the Nitro Group to Give the Primary Amine

(11) 28.0 mmol (products from step A1) or 56.0 mmol (products from steps A2/A3) SnCl.sub.2.2H.sub.2O were added to a solution of 8.0 mmol of the product from step A1/A2/A3 in 140 mL ethyl acetate at room temperature under stirring. The reaction solution was refluxed. The course of the reaction was monitored by means of thin-film chromatography (eluents: cyclohexane/ethyl acetate 1:1). Once the reaction was complete (approximately 2-3 h), the mixture was diluted with 70 mL ethyl acetate, a 10% aqueous potassium carbonate solution was added, and the mixture was stirred for 30 min at room temperature. The Sn compounds were filtered off and in the filtrate the aqueous phase was separated from the organic phase. The organic phase was washed with 100 ml (2) of a saturated aqueous sodium chloride solution and dried over magnesium sulfate. Following removal of the solvent in a vacuum, purification was performed by recrystallisation from dichloromethane and a few drops of n-hexane.

(12) Step C1Preparation of the Sulfonyl Urea Compounds

(13) A solution of 7.0 mmol of the corresponding sulfonyl isocyanate in 10 mL dichloromethane was added dropwise to a solution of 7.0 mmol of the product from step A1 in dichloromethane (20-40 mL) (additionally in 10 mL acetonitrile in the case of poor solubility) at room temperature under stirring. The reaction was monitored by means of thin-film chromatography (eluents: cyclohexane/ethyl acetate 1:1). Once the reaction was complete, the precipitated product was filtered off, washed with dichloromethane, and dried in a vacuum. In some cases the reaction solution was concentrated in the vacuum and the crystallisation was initiated by adding a few drops of n-hexane.

(14) Step C2Preparation of the Sulfonyl Urea Compounds

(15) A solution of 8.4 mmol of the corresponding sulfonyl isocyanate in DMF (5 to 10 mL) was added dropwise to a solution of 4.2 mmol of the product from step B in DMF (16 mL) under stirring. The reaction was monitored by means of thin-film chromatography (eluents: cyclohexane/ethyl acetate 1:1). Once the reaction was complete, the reaction solution was diluted with 100 mL ethyl acetate and washed with 100 mL (2) of a saturated aqueous sodium chloride solution and lastly washed with 100 mL water. Following removal of the solvent in a vacuum, purification was performed by recrystallisation from dichloromethane and a few drops of n-hexane.

(16) The compounds I to XIX (Table 2) were prepared starting from the corresponding phenylene diamines in accordance with the general provisions of steps A1 and C1.

(17) The compound XX (Table 2) was produced starting from 2,6-dinitroaniline, which was firstly converted into 1,2-diamino-3-nitrobenzene (reaction scheme 3, V. Milata, J. Salo, Org. Prep. Proceed. Int., 31 (3), 347 (1999)) and finally was converted into the end product in accordance with the general provisions of steps A1, B and C2.

(18) The compounds XXI to XXIV (Table 2) were prepared starting from 2,4-dinitroaniline (XXI and XXII), 4-nitro-1,2-phenylenediamine (XXIII), and 2,6-dinitroaniline (XXIV) in accordance with the general provisions of steps A1 (XXIII), A2 (XXI and XXII), A3 (XXIV), B (XXI-XXIV) and C2 (XXI-XXIV).

(19) The starting compounds are commercially available.

(20) TABLE-US-00002 TABLE 2 Compilation of selected compounds of formula (I) Y Ar.sup.1 Ar.sup.2 m n I 1,2-phenylene C.sub.6H.sub.5 C.sub.6H.sub.5 1 1 II 1,2-phenylene C.sub.6H.sub.5 4-CH.sub.3C.sub.6H.sub.4 1 1 III 1,2-phenylene 4-CH.sub.3C.sub.6H.sub.4 C.sub.6H.sub.5 1 1 IV 1,2-phenylene 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 V 1,2-phenylene 4-(tert-C.sub.4H.sub.9)C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 VI 1,2-phenylene 2,4,6-TriCH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 VII 1,2-phenylene 4-OCH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 VIII 1,2-phenylene 4-ClC.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 IX 1,2-phenylene 4-(NHCOCH.sub.3)C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 X 1,2-phenylene 4-NO.sub.2C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 XI 1,2-phenylene 2-(CO.sub.2CH.sub.3)C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 XII 1,2-phenylene 2-naph 4-CH.sub.3C.sub.6H.sub.4 1 1 XIII 1,2-phenylene C.sub.6H.sub.5CH.sub.2 4-CH.sub.3C.sub.6H.sub.4 1 1 XIV 1,3-phenylene* C.sub.6H.sub.5 4-CH.sub.3C.sub.6H.sub.4 1 1 XV 1,3-phenylene* 4-CH.sub.3C.sub.6H.sub.4 C.sub.6H.sub.5 1 1 XVI 1,3-phenylene* 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 XVII 1,4-phenylene* C.sub.6H.sub.5 4-CH.sub.3C.sub.6H.sub.4 1 1 XVIII 1,4-phenylene* 4-CH.sub.3C.sub.6H.sub.4 C.sub.6H.sub.5 1 1 XIX 1,4-phenylene* 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 1 XX benzene-1,2,3-triyl 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 2 XXI benzene-1,2,4-triyl 4-CH.sub.3C.sub.6H.sub.4 C.sub.6H.sub.5 1 2 XXII benzene-1,2,4-triyl 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 2 XXIII benzene-1,2,5-triyl 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 2 XXIV benzene-1,2,6-triyl 4-CH.sub.3C.sub.6H.sub.4 4-CH.sub.3C.sub.6H.sub.4 1 2 *comparative examples

(21) Analytical Data:

I, C.SUB.19.H.SUB.17.N.SUB.3.O.SUB.5.S.SUB.2., M=431.5, N-((2-(phenylsulfonamido)phenyl)carbamoyl)benzenesulfonamide

(22) MS (ESI): m/z (%)=430.0 (14) [MH].sup., 273.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 247.0 (15) [MHAr.sup.2SO.sub.2NCO].sup..

(23) *H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.66 (1H, s), 9.60 (1H, s), 8.57 (1H, s), 8.01-7.99 (2H, m), 7.86 (1H, dd, J=8.3, 1.3 Hz), 7.73-7.69 (1H, m), 7.68-7.62 (5H, m), 7.56-7.53 (2H, m), 7.16-7.12 (1H, m), 6.80 (1H, ddd, J=8.9, 7.9, 1.4 Hz), 6.39 (1H, dd, J=7.9, 1.1 Hz).

(24) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.12 (NHCONH), 39.78, 138.87, 135.56, 133.39, 133.01, 129.10, 129.03, 127.82, 127.27, 127.23, 127.08, 125.28, 123.15, 120.75.

II, C.SUB.20.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-((2-(phenylsulfonamido)phenyl)carbamoyl)tosylamide

(25) MS (ESI): m/z (%)=444.0 (23) [MH].sup., 273.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 247.1 (21) [MHAr.sup.2SO.sub.2NCO].sup..

(26) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.58 (1H, s), 9.60 (1H, s), 8.56 (1H, s), 7.89-7.86 (3H, m), 7.68-7.66 (2H, m), 7.65-7.62 (1H, m), 7.56-7.53 (2H, m), 7.44-7.43 (2H, m), 7.16-7.12 (1H, m), 6.79 (1H, ddd, J=8.9, 7.7, 1.4 Hz), 6.38 (1H, dd, J=7.9, 1.3 Hz), 2.39 (3H, s).

(27) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.16 (NHCONH), 143.93, 138.90, 136.95, 135.67, 133.02, 129.52, 129.05, 127.84, 127.37, 127.25, 127.10, 125.22, 123.08, 120.68, 21.00 (CH.sub.3).

III, C.SUB.20.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-(2-(3-(phenylsulfonyl)ureido)phenyl)tosylamide

(28) MS (ESI): m/z (%)=444.0 (17) [MH].sup., 287.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 261.1 (7) [MHAr.sup.2SO.sub.2NCO].sup..

(29) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.66 (1H, s), 9.51 (1H, s), 8.56 (1H, s), 8.01-7.99 (2H, m), 7.85 (1H, dd, J=8.3, 1.4 Hz), 7.73-7.69 (1H, m), 7.66-7.63 (2H, m), 7.56-7.54 (2H, m), 7.35-7.33 (2H, m), 7.15-7.11 (1H, m), 6.81 (1H, ddd, 9.1, 7.7, 1.4 Hz), 6.43-6.42 (1H, m), 2.36 (3H, s).

(30) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.13 (NHCONH), 143.34, 139.80, 136.07, 135.48, 133.38, 129.47, 129.09, 127.70, 127.26, 127.18, 127.13, 125.43, 123.16, 120.73, 20.96 (CH.sub.3).

IV, C.SUB.21.H.SUB.21.N.SUB.3.O.SUB.5.S.SUB.2., M=459.5, N-((2-(tosylamido)phenyl)carbamoyl)tosylamide

(31) MS (ESI): m/z (%)=458.1 (26) [MH].sup., 287.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 261.0 (10) [MHAr.sup.2SO.sub.2NCO].sup..

(32) .sup.1H-NMR (500 MHz, DMS0-d.sub.6): (ppm)=11.58 (1H, s), 9.50 (1H, s), 8.55 (1H, s), 7.89-7.85 (3H, m), 7.56-7.54 (2H, m), 7.44-7.42 (2H, m), 7.35-7.33 (2H, m), 7.15-7.11 (1H, m), 6.80 (1H, ddd, J=9.0, 7.7, 1.4 Hz), 6.43-6.41 (1H, m), 2.39 (3H, s), 2.36 (3H, s).

(33) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.15 (NHCONH), 143.88, 143.33, 136.98, 136.11, 135.59, 129.49, 129.45, 127.70, 127.36, 127.19, 127.15, 125.37, 123.07, 120.65, 20.98 (CH.sub.3), 20.94 (CH.sub.3).

V, C.SUB.24.H.SUB.27.N.SUB.3.O.SUB.5.S.SUB.2., M=501.6, N-(2-(3-tosylureido)phenyl)-4-tert-butylbenzenesulfonamide

(34) MS (ESI): m/z (%)=500.1 (56) [MH].sup., 329.1 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(35) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.57 (1H, s), 9.53 (1H, s), 8.55 (1H, s), 7.89-7.87 (2H, m), 7.86-7.85 (1H, m), 7.62-7.60 (2H, m), 7.58-7.56 (2H, m), 7.44-7.42 (2H, m), 7.14-7.11 (1H, m), 6.80-6.77 (1H, m), 6.42-6.40 (1H, m), 2.39 (3H, s), 1.28 (9H, s).

(36) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=156.10, 149.16 (NHCONH), 143.89, 136.96, 136.15, 135.48, 129.51, 127.66, 127.35, 127.03, 127.03, 125.84, 125.44, 123.05, 120.68, 34.83 (C(CH.sub.3).sub.3), 30.71 (C(CH.sub.3).sub.3), 21.00 (CH.sub.3).

VI, C.SUB.23.H.SUB.25.N.SUB.3.O.SUB.5.S.SUB.2., M=487.6, N-(2-(3-tosylureido)phenyl)-2,4,6-trimethylbenzenesulfonamide

(37) MS (ESI): m/z (%)=486.1 (37) [MH].sup., 315.1 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 289.1 (18) [MHAr.sup.2SO.sub.2NCO].sup..

(38) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.66 (1H, s), 9.26 (1H, s), 8.62 (1H, s), 7.89-7.87 (3H, m), 7.44-7.42 (2H, m), 7.18-7.14 (1H, m), 6.98 (2H, s), 6.77 (1H, ddd, J=9.0, 7.7, 1.4 Hz), 6.26 (1H, dd, J=7.9, 1.3 Hz), 2.39 (3H, s), 2.29 (6H, s), 2.24 (3H, s).

(39) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.26 (NHCONH), 143.87, 142.02, 138.89, 136.96, 136.06, 133.30, 131.54, 129.48, 127.99, 127.83, 127.35, 124.76, 123.09, 120.55, 22.42 (2xCH.sub.3), 20.98 (CH.sub.3), 20.36 (CH.sub.3).

VII, C.SUB.21.H.SUB.21.N.SUB.3.O.SUB.6.S.SUB.2., M=475.5, N-(2-(3-tosylureido)phenyl)-4-methoxybenzenesulfonamide

(40) MS (ESI): m/z (%)=474.1 (28) [MH].sup., 303.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(41) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.59 (1H, s), 9.42 (1H, s), 8.56 (1H, s), 7.89-7.85 (3H, m), 7.60-7.58 (2H, m), 7.44-7.42 (2H, m), 7.15-7.12 (1H, m), 7.07-7.05 (2H, m), 6.82 (1H, ddd, J=8.7, 7.7, 1.0 Hz), 6.43 (1H, dd, J=7.9, 1.1 Hz), 3.82 (3H, s), 2.39 (3H, s).

(42) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=162.53, 149.16 (NHCONH), 143.90, 136.96, 135.64, 130.47, 129.50, 129.34, 127.70, 127.34, 127.30, 125.46, 123.07, 120.58, 114.17, 55.60 (OCH.sub.3), 20.99 (CH.sub.3).

VIII, C.SUB.20.H.SUB.18.ClN.SUB.3.O.SUB.5.S.SUB.2., M=480.0, N-(2-(3-tosylureido)phenyl)-4-chlorobenzenesulfonamide

(43) MS (ESI): m/z (%)=478.0 (29) [MH].sup., 307.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 281.0 (49) [MHAr.sup.2SO.sub.2NCO].sup..

(44) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.56 (1H, s), 9.70 (1H, s), 8.55 (1H, s), 7.88-7.86 (3H, m), 7.67-7.65 (2H, m), 7.63-7.61 (2H, m), 7.44-7.43 (2H, m), 7.18-7.14 (1H, m), 6.84 (1H, ddd, J=9.2, 7.9, 1.4 Hz), 6.44 (1H, dd, J=7.9, 1.5 Hz), 2.39 (3H, s).

(45) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.13 (NHCONH), 143.93, 137.95, 137.77, 136.91, 135.65, 129.52, 129.24, 129.04, 128.00, 127.35, 127.28, 124.97, 123.26, 120.79, 21.00 (CH.sub.3).

IX, C.SUB.22.H.SUB.22.N.SUB.4.O.SUB.6.S.SUB.2., M=502.6, N-(4-(N-(2-(3-tosylureido)phenyl)sulfamoyl)phenyl) acetamide

(46) MS (ESI): m/z (%)=501.0 (32) [MH].sup., 330.1 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(47) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.60 (1H, s), 10.30 (1H, s), 9.45 (1H, s), 8.56 (1H, s), 7.89-7.86 (3H, m), 7.75-7.73 (2H, m), 7.60-7.57 (2H, m), 7.44-7.42 (2H, m), 7.15-7.12 (1H, m), 6.81 (1H, ddd, J=9.0, 7.6, 1.4 Hz), 6.40 (1H, dd, J=7.9, 1.4 Hz), 2.39 (3H, s), 2.09 (3H, s).

(48) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=169.01 (NHCOCH.sub.3), 149.19 (NHCONH), 143.91, 143.26, 136.96, 135.69, 132.36, 129.51, 128.38, 127.73, 127.35, 127.28, 125.41, 123.08, 120.59, 118.34, 24.11 (CH.sub.3), 21.00 (CH.sub.3).

X, C.SUB.20.H.SUB.18.N.SUB.4.O.SUB.7.S.SUB.2., M=490.5, N-((2-(4-nitrophenylsulfonamido)phenyl)carbamoyl)tosylamide

(49) MS (ESI): m/z (%)=489.0 (31) [MH].sup., 318.0 (55) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 292.0 (100) [MHAr.sup.2SO.sub.2NCO].sup..

(50) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.51 (1H, s), 9.97 (1H, s), 8.52 (1H, s), 8.40-8.37 (2H, m), 7.92-7.89 (2H, m), 7.87-7.84 (3H, m), 7.44-7.42 (2H, m), 7.20-7.16 (1H, m), 6.85 (1H, ddd, J=8.9, 7.7, 1.4 Hz), 6.48 (1H, dd, J=7.9, 1.3 Hz), 2.39 (3H,s).

(51) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.88, 149.13 (NHCONH), 144.49, 143.96, 136.89, 135.60, 129.52, 128.67, 128.24, 127.50, 127.33, 124.71, 124.47, 123.50, 121.08, 21.00 (CH.sub.3).

XI, C.SUB.22.H.SUB.21.N.SUB.3.O.SUB.7.S.SUB.2., M=503.5, methyl 2-(N-(2-(3-tosylureido)phenyl)sulfamoyl) benzoate

(52) MS (ESI): m/z (%)=502.1 (32) [MH].sup., 331.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 305.0 (31) [MHAr.sup.2SO.sub.2NCO].sup..

(53) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.53 (1H, s), 9.21 (1H, s), 8.53 (1H, s), 7.88-7.86 (2H, m), 7.82-7.81 (1H, m), 7.73-7.72 (2H, m), 7.67-7.65 (2H, m), 7.44-7.42 (2H, m), 7.18-7.15 (1H, m), 6.85-6.82 (1H, m), 6.55-6.54 (1H, m), 3.72 (3H, s), 2.39 (3H, s).

(54) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=167.35 (COOCH.sub.3), 149.29 (NHCONH), 143.90, 136.93, 136.57, 135.40, 133.17, 132.03, 130.94, 129.49, 129.13, 129.11, 127.91, 127.42, 127.34, 125.39, 123.43, 121.21, 52.87 (COOCH.sub.3), 20.98 (CH.sub.3).

XII, C.SUB.24.H.SUB.21.N.SUB.3.O.SUB.5.S.SUB.2., M=495.6, N-(2-(3-tosylureido)phenyl)naphthalene-2-sulfonamide

(55) MS (ESI): m/z (%)=494.1 (24) [MH].sup., 323.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 297.0 (26) [MHAr.sup.2SO.sub.2NCO].sup..

(56) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.64 (1H, s), 9.73 (1H, s), 8.64 (1H, s), 8.27 (1H, d, J=1.4 Hz), 8.13-8.12 (1H, m), 8.08-8.06 (1H, m), 8.04-8.02 (1H, m), 7.90-7.89 (2H, m), 7.89 (1H, dd, J=8.3, 1.3 Hz), 7.80 (1H, dd, J=8.7, 1.9 Hz), 7.71-7.68 (1H, m), 7.65-7.61 (1H, m), 7.45-7.43 (2H, m), 7.12-7.09 (1H, m), 6.71-6.68 (1H, m), 6.37-6.36 (1H, m), 2.39 (3H, s).

(57) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.19 (NHCONH), 143.92, 136.96, 135.95, 135.74, 134.29, 131.43, 129.52, 129.26, 129.19, 128.94, 128.34, 127.84, 127.81, 127.61, 127.37, 127.22, 125.21, 123.09, 122.45, 120.67, 20.99 (CH.sub.3).

XIII, C.SUB.21.H.SUB.21.N.SUB.3.O.SUB.5.S.SUB.2., M=459.5, N-((2-(benzylsulfonamido)phenyl)carbamoyl)tosylamide

(58) MS (ESI): m/z (%)=458.0 (16) [MH].sup., 287.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 261.1 (13) [MHAr.sup.2SO.sub.2NCO].sup..

(59) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.47 (1H, s), 9.25 (1H, s), 8.40 (1H, s), 7.86-7.84 (2H, m), 7.81 (1H, dd, J=8.4, 1.4 Hz), 7.39-7.34 (8H, m), 7.25-7.21 (1H, m), 7.10 (1H, ddd, J=9.0, 7.6, 1.5 Hz), 4.40 (2H, s), 2.36 (3H, s).

(60) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.33 (NHCONH), 143.87, 136.93, 134.39, 130.83, 129.46, 129.06, 128.33, 128.16, 127.52, 127.33, 127.33, 126.50, 123.97, 121.66, 57.25 (CH.sub.2), 20.98 (CH.sub.3).

XIV, C.SUB.20.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-((3-(phenylsulfonamido)phenyl)carbamoyl)tosylamide

(61) MS (ESI): m/z (%)=444.0 (100) [MH].sup., 272.9 (7) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(62) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.55 (1H, s), 10.24 (1H, s), 8.83 (1H, s), 7.86-7.84 (2H, m), 7.76-7.74 (2H, m), 7.59-7.56 (1H, m), 7.52-7.49 (2H, m), 7.43-7.41 (2H, m), 7.24-7.23 (1H, m), 7.10-7.07 (1H, m), 6.97 (1H, ddd, J=8.2, 2.0, 0.8 Hz), 6.76 (1H, ddd, J=8.1, 2.1, 0.9 Hz), 2.39 (3H, s).

(63) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.05 (NHCONH), 143.80, 139.46, 138.70, 138.19, 137.01, 132.79, 129.39, 129.39, 129.11, 127.45, 126.58, 114.42, 114.34, 110.23, 20.98 (CH.sub.3).

XV, C.SUB.20.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-(3-(3-(phenylsulfonyl)ureido)phenyl)tosylamide

(64) MS (ESI): m/z (%)=444.0 (100) [MH].sup., 287.0 (6) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(65) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.44 (1H, s), 10.17 (1H, s), 8.87 (1H, s), 7.99-7.97 (2H, m), 7.71-7.68 (1H, m), 7.64-7.61 (4H, m), 7.30-7.28 (2H, m), 7.24-7.23 (1H, m), 7.10-7.07 (1H, m), 6.97 (1H, ddd, J=8.2, 2.1, 0.9 Hz), 6.76 (1H, ddd, J=8.1, 2.1, 0.9 Hz), 2.30 (3H, s). .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.03 (NHCONH), 143.16, 139.90, 138.64, 138.34, 136.61, 133.28, 129.54, 129.36, 128.97, 127.37, 126.66, 114.27, 114.22, 110.04, 20.87 (CH.sub.3).

XVI, C.SUB.21.H.SUB.21.N.SUB.3.O.SUB.5.S.SUB.2., M=459.5, N-((3-(tosylamido)phenyl)carbamoyl)tosylamide

(66) MS (ESI): m/z (%)=458.1 (100) [MH].sup., 287.0 (4) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(67) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.53 (1H, s), 10.17 (1H, s), 8.82 (1H, s), 7.86-7.85 (2H, m), 7.65-7.63 (2H, m), 7.42-7.41 (2H, m), 7.30-7.28 (2H, m), 7.24-7.24 (1H, m), 7.10-7.06 (1H, m), 6.97-6.95 (1H, m), 6.77-6.75 (1H, m), 2.38 (3H, s), 2.30 (3H, s).

(68) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.05 (NHCONH), 143.80, 143.15, 138.68, 138.35, 137.03, 136.62, 129.54, 129.39, 129.36, 127.46, 126.67, 114.22, 114.17, 109.98, 20.99 (CH.sub.3), 20.87 (CH.sub.3).

XVII, C.SUB.26.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-((4-(phenylsulfonamido)phenyl)carbamoyl)tosylamide

(69) MS (ESI): m/z (%)=444.0 (100) [MH].sup., 273.0 (5) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(70) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.47 (1H, s), 10.05 (1H, s), 8.70 (1H, s), 7.84-7.62 (2H, m), 7.70-7.68 (2H, m), 7.58-7.55 (1H, m), 7.52-7.49 (2H, m), 7.40-7.39 (2H, m), 7.20-7.18 (2H, m), 6.99-6.97 (2H, m), 2.37 (3H, s).

(71) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.19 (NHCONH), 143.77, 139.39, 137.06, 134.61, 132.72, 132.72, 129.41, 129.09, 127.41, 126.59, 121.63, 119.83, 20.99 (CH.sub.3).

XVIII, C.SUB.20.H.SUB.19.N.SUB.3.O.SUB.5.S.SUB.2., M=445.5, N-(4-(3-(phenylsulfonyl)ureido)phenyl)tosylamide

(72) MS (ESI): m/z (%)=444.0 (100) [MH].sup., 287.0 (5) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(73) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.70 (1H, s), 9.98 (1H, s), 8.73 (1H, s), 7.96-7.95 (2H, m), 7.69-7.66 (1H, m), 7.62-7.57 (4H, m), 7.30-7.29 (2H, m), 7.20-7.18 (2H, m), 7.00-6.97 (2H, m), 2.30 (3H, s)

(74) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.16 (NHCONH), 143.04, 139.94, 136.56, 134.40, 133.25, 132.96, 129.51, 128.98, 127.31, 126.64, 121.41, 119.91, 20.87 (CH.sub.3).

XIX, C.SUB.21.H.SUB.21.N.SUB.3.O.SUB.5.S.SUB.2., M=459.5, N-((4-(tosylamido)phenyl)carbamoyl)tosylamide

(75) MS (ESI): m/z (%)=458.1 (100) [MH].sup., 287.1 (4) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(76) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=10.55 (1H, s), 9.97 (1H, s), 8.68 (1H, s), 7.84-7.82 (2H, m), 7.59-7.57 (2H, m), 7.40-7.39 (2H, m), 7.30-7.28 (2H, m), 7.20-7.17 (2H, m), 7.00-6.97 (2H, m), 2.37 (3H, s), 2.30 (3H, s).

(77) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.17 (NHCONH), 143.75, 143.03, 137.07, 136.56, 134.44, 132.91, 129.51, 129.39, 127.39, 126.63, 121.42, 119.84, 20.97 (CH.sub.3), 20.86 (CH.sub.3).

XX, C.SUB.29.H.SUB.29.N.SUB.5.O.SUB.8.S.SUB.3., M=671.8, N,N-(((3-tosylamido-1,2-phenylene)bis(azandiyl))bis(carbonyl))bis(tosylamide)

(78) MS (ESI): m/z (%)=670.0 (21) [MH].sup., 499.0 (100) [MAr.sup.2SO.sub.2NH.sub.2].sup., 302.0 (70) [MHAr.sup.2SO.sub.2NCOAr.sup.2SO.sub.2NH.sub.2].sup..

(79) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.38 (1H, s), 11.18 (1H, s), 9.47 (1H, s), 8.16 (1H, s), 7.91 (1H, s), 7.91-7.89 (2H, m), 7.80-7.78 (2H, m), 7.54-7.53 (1H, m), 7.49-7.47 (2H, m), 7.42-7.40 (4H, m), 7.29-7.28 (2H, m), 7.00-6.97 (1H, m), 6.42-6.40 (1H, m), 2.39 (3H, s), 2.38 (3H, s), 2.34 (3H, s).

(80) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=150.34 (NHCONH), 149.01 (NHCONH), 143.91, 143.64, 143.34, 137.20, 136.81, 136.01, 135.71, 133.30, 129.52, 129.50, 129.45, 127.22, 127.20, 126.89, 125.57, 122.98, 119.81, 119.08, 21.01 (CH.sub.3), 21.01 (CH.sub.3), 20.95 (CH.sub.3).

XXI, C.SUB.27.H.SUB.25.N.SUB.5.O.SUB.8.S.SUB.3., M=643.7, N,N-(((4-tosylamido-1,3-phenylene)bis(azandiyl))bis(carbonyl))bis(benzenesulfonamide)

(81) MS (ESI): m/z (%)=644.0 (79) [MH].sup.+.

(82) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.69 (1H, s), 10.62 (1H, s), 9.36 (1H, s), 8.94 (1H, s), 8.53 (1H, s), 8.00-7.98 (2H, m), 7.95-7.93 (2H, m), 7.91 (1H, d, J=2.5 Hz), 7.74-7.59 (6H, m), 7.52-7.50 (2H, m), 7.33-7.32 (2H, m), 6.86 (1H, dd, J=8.7, 2.5 Hz), 6.23 (1H, d, J=8.7 Hz), 2.35 (3H, s).

(83) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=145.05 (NHCONH), 148.98 (NHCONH), 143.35, 139.85, 139.72, 137.58, 136.32, 135.91, 133.45, 133.30, 129.47, 129.13, 129.01, 127.95, 127.35, 127.21, 125.84, 119.89, 113.18, 110.52, 20.98 (CH.sub.3).

XXII, C.SUB.29.H.SUB.29.N.SUB.5.O.SUB.8.S.SUB.3., M=671.8, N,N-(((4-tosylamido-1,3-phenylene)bis(azandiyl))bis(carbonyl))bis(tosylamide)

(84) MS (ESI): m/z (%)=670.0 (15) [MH].sup., 499.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 473.0 (2) [MHAr.sup.2SO.sub.2NCO].sup., 328.0 (5) [MH2xAr.sup.2SO.sub.2NH.sub.2].sup..

(85) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.60 (1H, s), 10.69 (1H, s),9.34 (1H, s), 9.18 (1H, s), 8.55 (1H, s), 7.91 (1H, d, J=2.4 Hz), 7.87-7.85 (2H, m), 7.82-7.80 (2H, m), 7.51-7.50 (2H, m), 7.45-7.43 (2H, m), 7.40-7.39 (2H, m), 7.32-7.31 (2H, m), 6.82 (1H, dd, J=8.7, 2.4 Hz), 6.24 (1H, d, J=8.7 Hz), 2.40 (3H, s), 2.38 (3H, s), 2.35 (3H, s).

(86) .sup.13C-NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.09 (NHCONH), 148.93 (NHCONH), 143.95, 143.76, 143.31, 137.61, 136.99, 136.87, 136.29, 135.91, 129.54, 129.42, 129.42, 127.92, 127.40, 127.38, 127.21, 119.77, 112.96, 110.27, 21.01 (CH.sub.3), 21.00 (CH.sub.3), 20.99 (CH.sub.3).

XXIII, C.SUB.29.H.SUB.29.N.SUB.5.O.SUB.8.S.SUB.3., M=671.8, N,N-(((2-tosylamido-1,4-phenylene)bis(azandiyl))bis(carbonyl))bis(tosylamide)

(87) MS (ESI): m/z (%)=670.0 (60) [MH].sup., 499.0 (100) [MHAr.sup.2SO.sub.2NH.sub.2].sup..

(88) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.38 (1H, s), 10.47 (1H, s), 9.47 (1H, s), 8.68 (1H, s), 8.33 (1H, s), 7.86-7.84 (2H, m), 7.82-7.81 (2H, m), 7.62 (1H, d, J=9.0 Hz), 7.54-7.52 (2H, m), 7.43-7.41 (4H, m), 7.28-7.26 (2H, m), 7.05 (1H, dd, J=9.0, 2.5 Hz), 6.76 (1H, d, J=2.5 Hz), 2.39 (3H, s), 2.38 (3H, s), 2.32 (3H, s).

(89) .sup.13C NMR (126 MHz, DMSO-d.sub.6): (ppm)=149.20 (NHCONH), 148.86 (NHCONH), 143.87, 143.78, 143.32, 137.05, 137.02, 135.99, 133.65, 129.88, 129.51, 129.45, 129.37, 127.43, 127.35, 127.02, 126.39, 121.75, 117.81, 117.28, 21.01 (CH.sub.3), 21.01 (CH.sub.3), 20.97 (CH.sub.3).

XXIV, C.SUB.29.H.SUB.29.N.SUB.5.O.SUB.8.S.SUB.3., M=671.8, N,N-(((2-tosylamido-1,3-phenylene)bis(azandiyl))bis(carbonyl))bis(tosylamide)

(90) MS (ESI): m/z (%)=670.1 (100) [MH].sup., 499.0 (33) [MHAr.sup.2SO.sub.2NH.sub.2].sup., 473.0 (29) [MHAr.sup.2SO.sub.2NCOAr.sup.2SO.sub.2NH.sub.2].sup., 328.1 (23) [MH2xAr.sup.2SO.sub.2NH.sub.2].sup., 302.0 (21) [MHAr.sup.2SO.sub.2NCOAr.sup.2SO.sub.2NH.sub.2].sup..

(91) .sup.1H-NMR (500 MHz, DMSO-d.sub.6): (ppm)=11.22 (2H, s), 8.91 (1H, s), 8.13 (2H, s), 7.84-7.82 (4H, m), 7.43-7.42 (4H, m), 7.40-7.38 (2H, m), 7.37-7.35 (2H, m), 7.19-7.17 (2H, m), 7.13-7.09 (1H, m), 2.39 (6H, s), 2.27 (3H, s).

(92) .sup.13C NMR (126 MHz, DMSO-d.sub.6): (ppm)=148.89 (NHCONH), 143.85, 143.78, 136.95, 136.62, 135.51, 129.44, 129.22, 128.40, 127.28, 126.87, 116.40, 115.44, 20.97 (CH.sub.3), 20.95 (CH.sub.3), 20.95 (CH.sub.3).

(93) An aqueous suspension to be applied for forming the heat-sensitive colour-forming layer of a heat-sensitive recording paper was applied on a laboratory scale by means of a doctor bar to one side of a synthetic base paper (Yupo FP680) with a grammage of 63 g/m.sup.2. Once dry, a thermal recording material sheet was obtained. The applied amount of the heat-sensitive colour-forming layer was between 3.8 and 4.2 g/m.sup.2.

(94) A heat-sensitive recording material or thermal paper was produced on the basis of the details provided above, wherein the following formulations of aqueous suspensions to be applied were used to form a composite structure on a carrier substrate, and then the further layers, especially a protective layer, were formed in the usual manner, which will not be detailed separately here.

(95) Preparation of the dispersions (in each case for 1 part by weight) for the suspensions to be applied

(96) An aqueous dispersion A (colour former dispersion) was prepared by grinding 20 parts by weight of 3-N-n-dibutylamino-6-methyl-7-anilinofluorane (ODB-2) with 33 parts by weight of a 15% aqueous solution of Ghosenex L-3266 (sulfonated polyvinyl alcohol, Nippon Ghosei) in a bead mill.

(97) An aqueous dispersion B (colour developer dispersion) was prepared by grinding 40 parts by weight of the colour developer together with 66 parts by weight of a 15% aqueous solution of Ghosenex L-3266 in the bead mill.

(98) An aqueous dispersion C (sensitisation agent dispersion) was prepared by grinding 40 parts by weight of sensitisation agent with 33 parts by weight of a 15% aqueous solution of Ghosenex L-3266 in a bead mill.

(99) All dispersions produced by grinding had a mean particle size D.sub.(4,3) of from 0.80 to 1.20 m. The particle size distribution of the dispersions was measured by laser diffraction using a Coulter LS230 apparatus from Beckman Coulter.

(100) A dispersion D (slip additive dispersion) was a 20% zinc stearate dispersion consisting of 9 parts by weight of Zn stearate, 1 part by weight of Ghosenex L-3266, and 40 parts by weight of water.

(101) Pigment P was a 72% coating kaolin suspension (Lustra S, BASF).

(102) The binder consisted of a 10% aqueous polyvinyl alcohol solution (Mowiol 28-99, Kuraray Europe).

(103) The heat-sensitive suspension to be applied was prepared by mixing, under stirring, of 1 part A, 1 part B, 1 part C, 56 parts D, 146 parts pigment P, and 138 parts binder solution (all parts by weight) under consideration of the order of introduction B, D, C, P, A, binder, and by bringing the mixture with water to a solids content of approximately 25%.

(104) The heat-sensitive coating suspensions thus obtained were used to produce composite structures of paper carrier and thermal reaction layer.

(105) The thermal recording materials were assessed as described hereinafter (see Tables 3, 4 and 5).

(106) (1) Dynamic Colour Density:

(107) The papers (strips 6 cm wide) were thermally printed with use of an Atlantek 200 test printer (Atlantek, USA) with a Kyocera printhead of 200 dpi and 560 ohms with an applied voltage of 20.6 V and a maximum pulse width of 0.8 ms with a chequered pattern with 10 energy gradations. The image density (optical density (o.D.)) was measured using a SpectroEye densitometer from X-Rite at an energy stage of 0.25 and 0.45 mJ/dot. The measurement uncertainty of the o.D. values was estimated at 52%.

(108) (2) Static Colour Density (Starting Temperature):

(109) The recording material sheet was pressed against a series of thermostatically controlled metal dies heated to different temperatures with a press-on pressure of 0.2 kg/cm.sup.2 and a contact time of 5 sec. (thermal tester TP 3000QM, Maschinenfabrik Hans Rychiger AG, Steffisburg, Switzerland). The image density (optical density) of the images thus produced was measured using a SpectroEye densitometer from X-Rite.

(110) The static starting point, according to definition, is the lowest temperature at which an optical density of 0.2 is achieved. The accuracy of the measurement method was 0.5 C.

(111) (3) Resistance Test of the Printed Image:

(112) a) Plasticiser Resistance:

(113) A plasticiser-containing cling film (PVC film with 20 to 25% dioctyl adipate) was brought into contact with the sample of the thermal recording paper, which had been dynamically recorded in accordance with the method under (1), avoiding folds and inclusions of air, then rolled up into a roll and stored for 16 hours. One sample was stored at room temperature (20 to 22 C.), and a second sample was stored at 40 C. After removal of the film, the image density (o.D.) was measured and set in relation to the corresponding image density values before the action of the plasticiser in accordance with formula (Eq. 1).

(114) b) Resistance to Adhesive:

(115) A strip of transparent self-adhesive tape from Tesa (tesafilm crystal-clear, #57315), and separately therefrom a strip of packaging adhesive tape from Tesa (#04204) were adhered to the sample of the thermal recording paper, which had been dynamically recorded in accordance with the method under (1), avoiding folds and inclusions of air. After storage at room temperature (20 to 22 C.), the image density (o.D.) was measured after 24 hours and after 7 daysthrough the particular adhesive tapeand, in accordance with the formula (Eq. 1), was set in relation to the similarly determined image density values of a freshly adhered specimen.

(116) $\begin{array}{cc}\%\mathrm{remaining}\mathrm{image}\mathrm{density}=\frac{\mathrm{image}\mathrm{density}\mathrm{after}\mathrm{test}}{\mathrm{image}\mathrm{density}\mathrm{before}\mathrm{test}}*100& \left(\mathrm{Eq}.1\right)\end{array}$

(117) The scattering of the % values calculated by (Eq. 1) was 2 percentage points.

(118) Tables 3 to 5 summarise the evaluation of the produced recording materials.

(119) TABLE-US-00003 TABLE 3 Image density (optical density with an energisation energy of 0.25 and 0.45 mJ/dot) and starting temperature (starting point) of the colour developer o.D. o.D. Starting Colour (0.25 (0.45 point developer mJ/dot) mJ/dot) ( C.) I 1.16 1.22 81 II 1.20 1.24 76 III 1.13 1.24 76 IV 1.19 1.20 71 V 1.17 1.20 76 VII 1.15 1.23 86 VIII 1.20 1.23 73 X 1.24 1.30 82 XIII 1.14 1.20 79 XXIII 1.16 1.26 82 XXIV 1.09 1.26 82 Z 1.19 1.24 86 PF201 1.19 1.23 76

(120) TABLE-US-00004 TABLE 4 Image density (optical density with an energisation energy of 0.25 and 0.45 mJ/dot) depending on the substitution pattern of the colour developer Relative position of o.D. o.D. Colour the sulfonamide and (0.25 (0.45 developer urea groups mJ/dot) mJ/dot) II 1.2 1.20 1.24 XIV 1.3* 1.05 1.16 XVII 1.4* 0.55 1.20 III 1.2 1.13 1.24 XV 1.3* 1.00 1.17 XVIII 1.4* 0.84 1.19 IV 1.2 1.19 1.20 XVI 1.3* 0.93 1.16 XIX 1.4* 0.57 1.19 *comparative examples

(121) TABLE-US-00005 TABLE 5 Resistance of the printed image of the colour developer Tesa adhesive tape* Plasticiser film* Colour 24 h 7 days 16 h developer #57315 #04204 #57315 #04204 R.T. 40 C. I 83 47 16 14 98 88 II 74 43 34 16 99 77 III 71 49 37 19 97 83 IV 71 42 32 14 98 89 V 67 38 18 11 97 68 VII 70 40 33 15 98 84 VIII 71 46 23 15 88 67 X 75 44 25 20 99 90 XIII 74 37 33 16 100 93 XXIII 92 90 74 65 94 92 XXIV 91 89 68 61 100 95 Z 60 35 12 13 83 17 PF201 73 46 32 16 97 78 *Percentage of remaining image density in accordance with Eq. 1

(122) It can be seen from the examples above that the heat-sensitive recording material of the present invention presents the following advantageous properties especially:

(123) (1) The recorded image of the heat-sensitive recording materials based on the colour developers according to the invention has print densities (optical densities) comparable to those of the comparison specimens from the prior art (Table 3).

(124) (2) The heat-sensitive recording materials based on colour developers with the substitution pattern according to the invention (1,2 position (ortho position) of the relevant functional groups) have significantly higher print densities than the recording materials based on colour developers with alternative substitution patterns (1,3 and 1,4 position of the relevant functional groups); see II with XIV and XVII, III with XV and XVIII and IV with XVI and XIX (Table 4).

(125) (3) The temperature from which a visually noticeable greying of the recording materials according to the invention occurred (static starting point) satisfies the requirements of marketable heat-sensitive recording materials (Table 3).

(126) (4) The image resistance after the action of hydrophobic agents (adhesives, plasticisers) is better than or comparable to the corresponding performance of the known non-phenolic colour developer materials according to the prior art (Table 5).

(127) (5) A heat-sensitive recording material of high quality in respect of key application properties can be obtained with the colour developers according to the invention. No recording material based on known colour developers has a comparable balanced performance profile across all tested properties.